Fixed other potential crashes with NSNull values. FTR, homeserver can send null values for displayname, avatar_url,status_msg and presence keys.
Fixed other potential crashes with NSNull values. FTR, homeserver can send null values for displayname, avatar_url,status_msg and presence keys.

vector-im/riot-ios,vector-im/vector-ios,vector-im/riot-ios,vector-im/vector-ios,matrix-org/matrix-ios-console,vector-im/riot-ios,vector-im/vector-ios,matrix-org/matrix-ios-console,vector-im/riot-ios,vector-im/riot-ios,vector-im/riot-ios